While screening a library of cationic amphiphiles for gene delivery activity, our laboratory identified a new cationic lipid preparation that was much more active than one of the most potent commercial standards. However, a second synthetic batch of this product had very low activity. Mass spectral analysis of the two batches revealed that the second poorly active batch was relatively pure, but the first highly active batch contained obvious impurities. The chemical identity of these impurities was ascertained from the mass spectra and a route to intentional synthesis of the impure product was devised. In this way the poorly active pure compound was converted into a chemically heterogeneous product that was as active as the original material. Although it is highly active, commercial distribution to the reagent and pharmaceutical markets of a chemically poorly defined preparation of this kind is problematic, since it is difficult to control and qualify batch-to-batch. It is therefore the purpose of this proposal to generate pure derivatives, evaluate their gene delivery potency and produce a potent chemically defined product suitable for commercial distribution to the reagent and pharmaceutical markets. PROPOSED COMMERCIAL APPLICATION The resources from this grant will be used to make more potent transfection reagents commercially available to scientists. Production methods and analytical quality control methods will be optimized and shelf-life stability studies will be initiated.